[Qgis-user] Support - representing a graph in Qgis

[Giacomo Uguccioni]

Thanks a lot!
I would like to represent a shapefile or more shapefiles of nodes and
connections (lines and points)
in a layout similar to an electrical scheme, a symbolic and conceptual
scheme and not a geographical one.
I attached an image with qgis view and output that I would like to get.

Il giorno mer 10 feb 2021 alle ore 01:25 Jorge Gustavo Rocha <
jgr at geomaster.pt> ha scritto:

> Hi Giacomo,
>
> Maybe it is better to share a sketch of what you want.
>
> 0) From the description of your use case, you can use the geographic
> position of the nodes, right? You might be able to do what you want just by
> creating points where you want to show the grid voltage and then create
> direct lines between nodes. If you can display it on the map, you don't
> need a graph.
>
> 1) Yes, you can use graphviz in the python console.
>
> 2) Graphviz does not read shapefiles. You have to iterate over your layer
> and generate the corresponding graph nodes and edges.
>
> Regards,
>
> Jorge Gustavo
> Às 23:06 de 09/02/21, Giacomo Uguccioni escreveu:
>
> Thank you guys for the support.
> Could I work with Graphviz in the python console inside Qgis? And does
> Graphviz support shapefiles or similar as an input?
>
> Il giorno mar 9 feb 2021 alle 20:07 Jorge Gustavo Rocha <jgr at geomaster.pt>
> ha scritto:
>
>> Hi,
>>
>> I second Chris's proposal. Using graphviz python module [1], you can
>> generate your graph by iterating over the features.
>>
>> At the end, just call the render and you will get the rendered graph
>> (just add view=True) within your QGIS environment. You need to know some
>> Python basic stuff, but not much than the basic.
>>
>> Regards,
>>
>> Jorge Gustavo
>>
>> [1] https://graphviz.readthedocs.io/en/stable/manual.html
>> Às 18:55 de 09/02/21, chris hermansen escreveu:
>>
>> Giacomo and list,
>>
>> On Tue, Feb 9, 2021 at 8:07 AM Giacomo Uguccioni <
>> giacomo.uguccioni at gmail.com> wrote:
>>
>>> Hello everyone, and thanks for the support.
>>> If this is not the place to ask for this kind of thing, I ask you to
>>> give me a link where I could find support.
>>> I'm a qgis 3.14 user. I would like to represent a tree diagram or
>>> functional diagram being able to draw the symbology and position of nodes
>>> and connections from the information contained in the attribute table.
>>> Example: I would like to represent the medium voltage grid of a city as an
>>> electrical diagram; I would like to represent with lines that join at nodes
>>> the roads that connect certain houses and schools in a city. So my goal is
>>> to be able to build a layout with symbology of nodes and connections
>>> derived from information contained in different shapefiles or within
>>> features, with a non-geographic but schematic / ideal criterion.
>>> Do you have any ideas or suggestions on how to do it? I thank you for
>>> every contribution.
>>>
>>>
>> Not a QGIS-based solution, but I've used graphviz <https://graphviz.org/>
>> to generate graphs from the command line with considerable success.  It
>> offers a small but useful programming language that can be combined with
>> data in text files in a really useful way.
>>
>> --
>> Chris Hermansen · clhermansen "at" gmail "dot" com
>>
>> C'est ma façon de parler.
>>
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>> *Geomaster*
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> --
> *Giacomo Uguccioni*
> *Geospatial Data Acquisition & Processing*
> +39 3920431219
> Le informazioni contenute nella presente comunicazione sono riservate
> esclusivamente ai destinatari indicati in epigrafe. La diffusione del
> documento trasmesso da parte di qualsiasi soggetto diverso dal mittente e
> dal destinatario è proibita, sia ai sensi dell’art. 616 c.p., sia ai
> sensi del D.Lgs. n. 196/2003 e regolamento UE n. 2016/679.
> Se avete ricevuto questo messaggio per errore, vi preghiamo di
> distruggerlo e di darcene immediata comunicazione anche inviando un
> messaggio di ritorno all’indirizzo e-mail del mittente.
>
> --
> [image: Logo] <https://www.geomaster.pt>
> *Geomaster*
> *Jorge Gustavo Rocha* | Software Engineer
> *e:* jgr at geomaster.pt | *m:* +351 910 333 888
> *g:* 41.54094,-8.40490 | *v: * 510 906 109
> *a: * Rua António Cândido Pinto, 67, 4715-400 Braga
>


-- 
*Giacomo Uguccioni*
*Geospatial Data Acquisition & Processing*
+39 3920431219
Le informazioni contenute nella presente comunicazione sono riservate
esclusivamente ai destinatari indicati in epigrafe. La diffusione del
documento trasmesso da parte di qualsiasi soggetto diverso dal mittente e
dal destinatario è proibita, sia ai sensi dell’art. 616 c.p., sia ai
sensi del D.Lgs. n. 196/2003 e regolamento UE n. 2016/679.
Se avete ricevuto questo messaggio per errore, vi preghiamo di distruggerlo
e di darcene immediata comunicazione anche inviando un messaggio di ritorno
all’indirizzo e-mail del mittente.
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